This doesn't check for fine calibration, just makes sure the part is
within the broad tolerances specified by the manufacturer. The subtle fix
here was actually getting reset working -- there was a typo in the
bitpattern definition which caused the reset to fail, making it hard
to self-test the part, as self-test is only valid before the part is running.
Signed-off-by: Keith Packard <keithp@keithp.com>